The invention herein relates to refractory compositions of material which can be shaped, as by molding or extruding, and in their shaped configuration can be used in contact with molten aluminum.
Over the past years, a large number of materials have been used in the aluminum industry to convey and handle the molten metal. A particularly troublesome area has been found in the troughs through which the molten metal is poured, and several types of materials have been used for such troughs. In some cases the troughs have been built up out of refractory cements. This, however, has required the construction of a trough-shaped frame which is thereafter coated with the refractory cement lining. Such in-line construction has been quite expensive in terms of the hand crafting required, plus there is a substantial amount of time during which the molten metal production facility must be down.
Another approach to the handling of the molten aluminum has been to construct the troughs out of flat boards made of refractory materials. One type of material which has proved highly successful for such use in that sold under the trademark "MARINITE" by the Johns-Manville Corporation. While this composition has proved to have excellent service characteristics, it is manufactured only in the form of flat boards. Three flat boards must therefore be joined together in a "U" shape to form the desired trough for conveying the molten metal. This of necessity means that each trough contains longitudinal joints between adjacent boards. Such joints have in the past led to problems of metal loss through the joints and deterioration of the troughs at the joints.
It will thus be apparent that there is a distinct need for a material from which unitary troughs can be shaped at factory locations and then merely installed on site at the molten metal processing facility. Such preformed unitary troughs can be readily and easily installed where they are to be used with minimum downtime of the molten metal casting equipment. Further, their unitary nature eliminates longitudinal joints.